Effect of Long-chain Branching on Surface Dynamics of Polymer Films

ORAL

Abstract

Thermally stimulated fluctuations of the surface of films of branched polystyrene chains have been studied using x-ray photon correlation spectroscopy (XPCS), a recently-developed technique that has already been applied to study the surfaces of melts of linear polystyrene chains. Surface relaxations of films of branched chains are faster than are those of films of linear analogs. However, the Tg's of the branched molecules are also lower. The variation in surface relaxation time as a function of scattering vector can be described well by a continuum hydrodynamic theory of thermally stimulated capillary waves with a nonslip boundary condition. However, the film viscosities inferred from fits of the theory to the data differ markedly from viscosities from bulk measurements. Acknowledgements: NSF support (CBET 0730692)

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Authors

  • Mark D. Foster

    • Department of Polymer Science, The University of Akron, Akron, OH 44325-3909
    • Dept. of Polymer Science, The University of Akron
    • Department of Polymer Science, The University of Akron
    • University of Akron, Dept of Polymer Science
    • Department of Polymer Science, The University of Akron, Akron, OH 44325

  • Shih-Fan Wang

    • University of Akron
    • Dept. of Polymer Science, The University of Akron

  • Jae Sik Lee

    • Dept. of Polymer Science, The University of Akron

  • Sewoo Yang

    • Dept. of Polymer Science, The University of Akron

  • Zhang Jiang

    • X-ray Science Division, Argonne National Lab
    • Experimental Facilities Division, Argonne National Laboratory, Argonne, IL 60439

  • S. Narayanan

    • Argonne National Laboratory
    • Argonne National Laboratories
    • X-ray Science Division, Argonne National Lab
    • ANL-APS

  • David Wu

    • Colorado School of Mines